Tmv Y Arabidopsis Thaliana

ABSTRACT

Viral infections and their spread throughout a plant require numerous interactions between the host and the virus. While new functions of viral proteins involved in these processes havebeen revealed, current knowledge of host factors involved in the spread of a viral infection is still insufficient.

In Arabidopsis thaliana, different ecotypes present varying susceptibi-lities to Tobacco mosaic virus strain U1 (TMV-U1). The rate of TMV-U1 systemic movement is delayed in ecotype Col-0 when compared with ecotype Uk-4.

To discard that delayed systemic movementin Col-0 was due to a difference in local virus movement, we monitored the time course of the infection in the inoculated leaf for both ecotypes. The viral coat protein was detected by Western blot inthe inoculated basal leaves starting from 4 dpi in both ecotypes, indicating that the local movement of the virus is not affected by the genetic background.


Ecotypes Col-0 x Uk-4 werecrossed and F1 and F2 progeny were analysed for systemic movement. It was determined that delayed systemic movement for Col-0 was correlated with a recessive, monogenic and nuclear locus. This locus wasnamed DSTM1.


For genetic mapping analysis of the DSTM1 locus, F2 progeny plants from the Uk-4 x Col-0 cross were used. Fifty six TMV-U1 resistant individuals selected for absence of CP innon-inoculated upper leaves at 12 dpi were screened. Co-segregation of this character with different polymorphic molecular markers was studied for each of the five A. thaliana chromosomes. Recombinationfrequencies between DSTM1 locus and the markers on chromosome II were less than 50 %, strongly suggesting that DSTM1 is located in this chromosome. Based on recombination frequencies between DSTM1locus and the markers, the DSTM1 locus was mapped on the long arm of chromosome II, between ATIPT2 and F24D13.7 CAPS markers. These two markers, at a distance of 169926 bp from each other, showed the...